Solutions-Class 8-Science-Chapter-10-Cell and Cell Organelles-Maharashtra Board

A. Mitochondria

B. Vacuole

C. Endoplasmic Reticulum

D. Chloroplasts, Mitochondria, Golgi complex, Chloroplast, Ribosomes etc. can be called chemical factory of cell

E. Chloroplast

• Mitochondria continuously carry out oxidation and form energy inside the cell. They produce energy rich compound, ATP. In this process, they utilize carbohydrates, fats and proteins present in the cell.
• RBC's are a type of cells which are found in blood. Their function is to carry oxygen to different cells and tissues of the body.
• If RBCs has mitochondria, they would have used oxygen for this purpose than carrying it to all the cells of the body. Thus, there will be less or no oxygen left which can be transported to the cells and tissues.

• Mitochondria and plastids are two different structures and they have specific functions.
• Mitochondria are found in both plants and animals whereas plastids are found only in plants.
• The main role of mitochondria is to provide energy to the cells for carrying out their various functions.
• Plastids are synthesizing carbohydrates with the help of solar energy and chlorophyll.
• Both the cell organelles have their own sets of different enzymes as per their role.
• If there would have been no difference between mitochondria and plastids, the specific functions would not have been taken place.

• Genes are functional segments on the chromosomes.
• Genes are hereditary structures which contain the information which is passed on from one generation to another.
• The protein synthesis process also is initiated due to genes.
• If genes were absent, these processes will be ended.

• Selectively permeable membrane allows some substances to enter the cell, while prevents other unwanted or harmful substances.
• If plasma membrane would not have been selectively permeable, the regulated movement of substances in and out of the cell will be affected, there would be no control over entry and exit of any substances.
• The process of osmosis would also be erroneous in such case.

• If plants lacked anthocyanin, no part of the plant would display purple or blue colour.
• Anthocyanin attracts the insects for pollination and seed dispersal.
• These processes will be affected due to lack of anthocyanin.
• These pigments are also said to be protective in nature for the plant.
• This protection will not be given to the plant in absence of anthocyanin.

Nucleolus is odd one. All the others arecell organelles but nucleolus is not a cell organelle present in cytoplasm.

Chlorophyll is the odd one out because it is a type of pigment which is found in plants only. DNA and ribosomes are found in both plants and animals.

Plasma membrane acts as a selectively permeable membrane. It allows entry of those useful substances which are needed for the cell. It does not allow entry of the harmful and unwanted substances.

• It gives shape and support to the cell.
• Plasma membrane is responsible for processes of endocytosis and exocytosis.
• It acts as a mechanical barrier to protect the internal contents of the cell.
• It separates the contents of the cell from its surrounding medium. 
• It performs physical activities such as diffusion and osmosis. 

Functions of cytoplasm:

• All the cell organelles are spread in the cytoplasm of a cell.
• It is the medium for all cellular chemical reactions.
• It is a medium in which the organelles remain suspended.
• It helps in the movement of the different cellular elements. 
• The cytosol which is the part of cytoplasm other than cell organelles stores many vital substances like amino acids, glucose, vitamins, etc.

Functions of lysosomes:

• Lysosome helps in the destruction of attacking viruses and bacteria and thereby help in the immune response.
• Dead and worn-out organelles are removed by lysosomes.
• Cells are autolysis by lysosomes, and their contents are released within the cell.
• They are also called suicide bags as in a worn out, damaged or old cell, lysosomes automatically burst. The lytic enzymes present in the lysosome digest their own cells.
• Lysosomes can digest stored proteins, fats during starvation.

Functions of vacuoles:

• Vacuoles maintain the osmotic pressure of the cell.

• The main function of vacuoles is to store food in a cell.
• They also help in storing and expelling wastes and toxic by products of metabolic reactions.
• They help in maintaining the turgidity and rigidity of a cell as it contains good amount of cell sap.

Functions of nucleus:

• It is the control centre of a cell as it controls all the activities of the cell.
• It controls all metabolic activities of the cell.
• The cell division is possible due to the nucleus.
• The chromosomes present in the nucleus carry the genes.
• These genes are responsible for the transmission of hereditary characters from parental generation to the next generations.